Lifting jack



o 3 w. F. KRENZKE 1,829,662

LIFTING JACK I Filed Aug. 5, 1928 2 Sheets-Sheet 1 M j 1 if OTTEQE Oct.27, 1931. w. F. KRENZKE LIFTING JACK Filed Aug. 5

2 Sheets-Sheet 2 35 lifting members.

" lng' member 'carrl Patented 27,

asarolon 'ro wanna mamamo 001mm; A oonrona'rr'ou'or wrsoom ammo no:

' A turias me an: a, m. 'urm 10.897).

This invention relates t'o' new and useful improvements in liftingLacks, and more par-' ticularly to a screw ac not: the double exjtensiontype, design to have a long lift in 5 proportion to the sim and heightof the jack when in lowered or collapsed position. 7

The jack is of that type. employing a plurality of telescopicallyengaged 'ftmg and guide members, certain of which have screw 1 threadeddriving connections with one another, and others being keyed-together topermit vertical sliding movement without permitting relative rotatio'mThe general ob'ect of this invention is to as provide a jack 0 ,this'type,-fas disclosed in etail hereinafter, which is capable of a maximumelevation inproportion to the-ilk itial height of the jack andz thenumber of telescoping members Y m'g gear mounted inthe lower end of thesupportin standard, so that the power may be most e ectively applied,while at the same time permitting a maximum lowering'of the Anotherobiect is to rov ide an improved form. of sheet'metal gui e-sleeve.

Another object is to provide-means for causing the guidesleeve to beelevated with the upper lifting member until the guide sleeve'hasreached its. maximum elevation. Another object is to rovide a jack ofthis type which is simple and economical to manulecture, and easilyassembled. j Other objects and advantages ofithis invention will be moreapparent from the following detailed description of one approved .formof the mechanism,

Inthe accompanying drawings:

' Fig. 1 is a pe tive elevation of the completely extendeii jack. M Fig.2 is a central vertical section through the jack,..when extended, asshown in Fi 1. '-'-F1g. 3 is a, similarcentral vertical section, showingthe jack completely lowered. Fi 4 is -a horizontal section, takensubstantlally on the line of Fig. 3;

Fig: 5 is a detail perspective, on a la r;

scale, of the drivin gear and tubular du thereby.

'tion 50 r The supporting standard comprises a suitablebase plate 1, anda'hollow standard 2 which may be made of malleable iron, or of. Y ressedsteel. parts suitably assembled. tandard 2 comprises an enlar lower endrtion 3 havin aniout-turn end flange 4 y means of .w ich the standard issecured to base late 1. The smaller upper end orstandard 2 is inthe formof a c'y lindrical guide portion, ha a vertical proection 6 at onesidewhich ouses the verti' cal guidegroove 7. An outwardly extend ingand upwardly inclined tubularbearing 8 ormedjn one side wall of standard2 intermed ate its upper and lower ends, receives 1 the ournal 9 of thedriving pinion 10. -A han wheel or disc '11, for conveniently rotat-.ing the driving pinion,'is mounted on the outor end of ournal 9, and anon-circular socket Another object is to provide a cupp d driv- 12 injournal 9 is adapted to receive the correspondm ly aha dend of adrihandle, who by t e jac may be operafi from a distance when lifting orlowerin the load'.

The improved driving gear (s own in' per- 'spectlve in Fig. 5) comprisesa base portion 75 or disc 13, from which arise the verticalsubstantially cylindrical side walls 14. 'An inwardly' extending fiange15 at the u per end of cylindrical portion 14 is 'formed with an annularseries of gear teeth 16 adapted to mesh with the driving pinion 10. Thelower outer edge portion of this gear member is meet or curved inwardly,as indicated at 17,- to housethe members of an annular roller bearing18. This bearing comprises lower race-way 19 carried by base late 1 andcenter'ed by engagement with t e lower end of standard 3, and an upperrace-way 20 centered in the annular depression 17 in the gear. member.In this manner the gear member is rotatably supported from the base 1,and centered within standard 2, with the base portion '13 of the' gearpositioned :-as closely as possible to the base plate 1 and thecylindrical outer walls 14 of the gearmember closely adjacent the sidewalls of standard 2, sothat I the'lifting members, hereinafterdescribed,-'

may be telescoped within the gear member with their lower edges broughtinto'close PTO. or o the base s of the ear,- a no closely as maximumowering of the ssible to base plate 1, whereby a ifting members is madepossible.

A, hollow tubular driving member 21' is mounted at its lower end in base13 of the of. A stop 25 secured in the lower end portionfl ofscrew 23,.is adapted to engage the lowenend: of threads 24 to limit the upwardengagesthe inset portion at the upper movement of the screw.

An enlarged head 26 exteriorly threaded at 27', iskeyed on the upper endof screw 23, as-indijcated'at 28. An upper tubular liftmember 29 isinteriorly threaded at 30 to receive the head 26. The upper end oflifting member 29is(provided with 'a suitable loadengaging hea or plate31.

ide sleeve 32 is preferably formed of sheet material: bent toformahollow cylindrical portion which will fit telescopically within theupper cylindrical end '5 of standard"2,*and-a vertical hollow rib 33adapted to slide within the groove 7 in the standard.

This ribmay be conveniently formed by bending-outwardly the walls of thesleeve, as indicated'at 34 and 35, and then bending toward one anotherand overlapping the ends 36 and 37 of the sheet from which thetube isformed; These overlapping wall portions may be united by welding, or byrivets, as-indicated at 38 and 39. As here shown, the

lower rivet 38 serves as a stop member, which endof groove {of thestandard for limiting the upward movement of sleeve 32. It will beapparent that the engagement of rib 33v within the groove .7 in thestandard will. prevent relative rotation between the guide sleeve 32 andthe standard, and an outwardly cylindrical Surface of 1i g e 29 r -meextending projection 41' onthe'lower end of the uper lifting member 29slides in the V groove 42- formed in. hollow rib 33 so asto preventrelative rotation between the sleeve 32 and lifting member 29. Since thesup-'- porting standard is held from rotation by its engagement with theground or other supporting surface, it will be apparent that the' upperlifting member 29, which supports the load,.is'never permitted'torotate. I A spring latch 43 is mounted in the upper rtionofgroove '42 insleeve 32, as by means of the rivet. 39. The finturn'ed finger--44 atthe upper end of spring latch 43 is adapted to detachably engage .in anotch 45 formed ad acent the upper end of lifting member 29.

The latch is shown in engaged or latching position in Fig. 3. v

When the jack is completely lowered, as shown in. Fig. 3, all of thelifting and guide members will'be completely housed within the standard2. 'It will be noted that the screw 23 can be made of iajmairimum lengthso as to extend completely down to the base plate 1. The guide sleeve 32and upper liftmg'member 29 telescope-down= over'1thetubu- I lar drivingmember 21, and'withinthe cu shaped gear member so as to-extend at theirlower ends closely adjacent the base 13 of th'gNgear.

hen the driving pinion is rotated in the proper direction for elevatingthe jack, the. lifting screw 23 which is held from rotation,

due to its engagement with upper lifting tional resistance between thethreaded head 26 and the internally threaded liftingmember 29 than thereis between the screw 23 and the'nut 24) will bejelevated through the nutit will be forced to rotate with'the tubular.

driving member 21, thus rotating head 26 with n theupper lifting member29 andicausing that member to be raised out of guide sleeve 32. Whenfurtherupward movement ofguide sle'eve 32 is prevented by thestop. '38engagmg the. stop 40 on thev standard, the

spring latch 43 willsnap out of the notch '45. and permlt the liftingmember. 29 to move upward to the extreme position shown in Fig. 2, wherefurther elevation of thejack mem- I hers is prevented by theen agementof projection 41 with the lower en of latch member 43. During thislatter movement oflifting member 29, the finger44 on spring latch 43Wlll. simply bear yieldingly against the outer The jack 'is againlowered by alreverserota tion of the driving pinion,..and';-when themember 29, (there usually being greater fric-,

members have been completely :telescoped ber 29, as shown in Fig. 3.

By providing means for causing gtlie sleeve 32 to be elevated duringthe[first half of' thef load-lifting op ration, the lifting members areadditionally stifiened during this phase of the movement,% and' thesleeve 1. In a lifting'ieckye sibi iit isias within the standard, thespringjlatch 43 will gain snap lntothe notch45in lifting mem- 5 in gearconsisting of a horizonta base, a

su stantially cylindrical portion arising therefrom adjacent theinnerside walls of the standard, and an annular series of gear teethformed at the upper end of the cylindrical portion and-adapted to meshwith the driving pinion, an annular bearing inset in the outer edgeportion of the driving gear for supporting same from the base plate withthe gear base positioned closely ad acent the base plate, an upright,hollow c lindrical driving member mounted central y in the gear baseandsecured thereto, the upper end portion of this member being interiorlythreaded, a lifting screw meshing with these threads and adapted totelescope within the driving member, an exteriorly threaded head 'on theupper end of the screw, a hollow interiorly threaded lifting member inwhich the head meshes, a hollow ide sleeve formed with an outwardlyprojecting hollow vertical rib atone side thereof, the up r ortion ofthe standard being formed to slidably receive the sleeve and rib, thelower end of the lifting member having a' projection thereon adapted toslide vertically in the hollow rib, sto' members on the standard andsleeve, an .a spring latch mounted in the upper portion of the hollowrib of the sleeve and detachably engaging the lifting member so that thesleeve will be carried up with the lifting e engagement of standardcarried thereby, a driving pinion mounted in one wall of the standard, ahorizontally disposed drivin gear meshing with gear from the base plate,a tubular vertically extending driving member mounted centrally on thedriving gear, the tubular member being interiorly threaded at its upperend, a lifting screw threadedin the tubular member, an exteriorlythreaded head mounted at the top of the lifting screw, a hollowinteriorly threaded lifting member in which the head meshes a hollowguide sleeve telescopically engaging the standard and the hollow liftinmember, there being slidably interengage fportions on the sleeve,standard and lifting member to prevent relative rotation of thesemembers, a stop for limiting the upward movement of the sleeve, and aspring latch detachably connecting the sleeve and lifting member so thatthe sleeve and lifting member will be elevated as a unit until the thesleeve.

3. In a lifting jack, a supporting member standard carried thereby, adrivin on the comprising a base plate and a hollow upright the pinion, ahearing. or supporting the comprising a base plate and a hollow uprightpimon mounted in one wall of the standar a horizontally disposed drivinggear meshing with the pinion, a bearing for supporting the gear from thebase plate, a tubular vertically extendin driving member mountedcentrally driving gear, the tubular member being interiorly threaded atits u per end, a lifting screw threaded in the tu ular member, anexteriorly threaded head mounted at the top of the lifting screw ahollow interiorly threaded lifting member in which the head meshes, ahollow ide sleeve telescopically engaging the stan ard and the hollowlifting member, there being slidably interengaged portions on thesleeve, standard and lifting member to prevent relative rotation ofthese. members, stop members on the sleeve and standard for limitingupward movement of the sleeve, and a spring latch mounted in the upperend of the sleeve and detachably engaging the lifting member so that thesleeve will be carried up with the lifting member until further upwardmovement thereof is prevented b the sto members.

.4. In a lifting jaclz, a hol ow standard formed at its upperend with acylindrical portion with a vertical guide groove rojecting outwardlyfrom one side thereo a hollow cylindrical guide sleeve formed with ahollow longitudinal rib rojecting outwardly therefrom and slidab yreceived in the groove, a cylindrical lifting member telescopicallyreceived in the sleeve and having a projection on its lower end portionslidable in the hollow rib, and means mounted in the standard andengaging the lifting member for raising and lowering the sam 5. In alifting jack, a hollowstandard formed at its upper end with acylindrical portion with a vertical guide groove proilectmg outwardlyfrom one side thereof, a ollow cylindrical 'de sleeve formed with ahollow lon 'tudinalrib wardly there om and slida 1 received in the.groove, a cylindrical lifting member telescopically received in thesleeve and hav-. mg a projection on its lower end rt-ion slidable in thehollow rib, stop rs on the standard and sleeve, and a spring latchrojecting out mounted in the hollow rib and detachably the standard andengaging-the lifting her for raising and lowerin the a 6. In a liftingjack, a ollow'standara formed at its upper end with a cylindricalportion with a vertical guide groove'fprr; 'l:::,t, stop-preventsfurther upward movement of a: L

ing outwardly from one side theneo A low guide sleeve formed of sheetmetal to form a cylindrical portion and an oute engagement of H Ivard1y' ;-extending hollow vertical rib, the edgedof the metal sheetbeinfi) overlap iei;

to-form the outer well-of the n the rib -.ing slidahly received in thegroove ofthe .5-standa-rd,' a, cylindrical lifting member telescopically received in the sleeve and having 1 a rojection on its lowerend portion slidab e in the hollowrib, and means moun in the standardand engaging the 0; member to raise and lower the same.

AM F. KRENZKE.

